Roof support assembly suitable for use in mines



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ROOF SUPPRT ASSEMBLY SUITABLE FR USE IN MNES ATToraNEv Aug- 9, 1966 D. H. H. BOLTON ETAL 3,264,945

ROOF SUPPORT ASSEMBLY SUITABLE FOR USE IN MINES Filed May 15, 1965 2 Sheets-Sheet 2 'l'.NvEN-rovas )uhmm H.H 'Bul-Tm Bv FRANZ 'PAWLING MHHAEL c. :PTTS

AT1-ORNE# United States Patent 3,264,945 ROOF SUPPORT ASSEMBLY SUITABLE FOR USE IN MINES Douglas Herbert Hewlett Bolton, Winchcombe, Frank Pawling, Charlton Kings, and Michael Charles Potts, Prestbury, England, assiguors to Dowty Mining Equipment Limited Filed May 13, 1965, Ser. No. 455,540 Claims priority, application Great Britain, May 15, 1964, 20,383/ 64 6 Claims. (Cl. 91-170) This invention relates to roof support assemblies suitable for use in mines.

The present invention provides a roof support assembly including a series of advanceable roof supports, each roof support having `at least one iluid-pressure-operated prop operable to set the support against a roof and a fluidpressure-operated jack operable to advance the support, each roof support also having a valve assembly controlling operation of the prop and the jack, the valve assembly being operated by the receipt of a signal from the preceding roof support in the series to cause its roof support to undergo an advancing operation, and the valve assembly being responsive to the satisfactory completion of the advancing operation of its roof support to send a signal to the next roof support in the series, the assembly also including a source of uid pressure which, when a roof support is undergoing an advancing operation, supplies iluid under pressure through the valve assembly of the roof support to the prop and jack thereof, and isolating means operable from a position remote from the roof supports to isolate from the source of iluid pressure the prop and jack of a roof support which Ahas received but not passed on the signal.

Each valve assembly may include a valve associated with a line which remains unpressurised until its roof support receives the signal from the preceding roof support, and the operation of the isolating means actuating the valve of every assembly, each valve assembly being so arranged that a valve actuated by the by-passing means isolates the associated prop and jack from the source of fluid pressure and continues such isolation .after operation of the isolating means has taken place if the line associated with the valve is pressurised.

The signal may be a fluid-pressure signal which supplies the fluid pressure for the line. The iluid-pressure signal may originate from the source of lluid pressure and pass through the valve assembly to the prop and jack, the isolating means functioning by isolating the signal from the prop and jack.

The present invention also provides a roof support assembly including a series of advanceable .roof supports, each roof support having at least one fluid-pressureoperated prop operable to set the support against a roof and a iluid-pressure-operated jack operable to advance the support, each roof support `also having a valve assembly controlling operation of the prop and the jack, the valve assembly being operated by the receipt of a signal from the preceding roof support in the series to cause its roof support to undergo an advancing operation, the valve assembly being responsive to a satisfactory completion of an advancing operation of its roof support to send a signal to the next roof support in the series, the valve assembly including a line whose pressurisation causes release of the prop from a roof-supporting condition and actuation of the jack in a support-advancing manner, and the valve assembly operating to -release pressure from said line when the signal is sent to the next roof support.

One embodiment of the present invention will now be described, by way of example, with reference to the accompanying `drawings of which,

- Patented August 9, 1966 ICC FIGURE 1 is a diagrammatic view of a series of advanceable roof support arranged along the working face of a coal-mine,

FIGURE 2 is a diagrammatic view of three roof supports of the series, showing the hydraulic connections to each roof support and,

FIGURE 3 is a diagrammatic view of the hydraulic circuit of one of the roof supports.

With reference to the accompanying drawings, a series of roof supports 1 are Iarranged along the working face 2 of a coal-mine. Each roof support 1 includes a floorengaging member 3 which carries three hydraulicallyoperated props 4, and the three props 4 carry a roofengageable member (not shown). Each root` support 1 is connected .to a snakeable conveyor 5 by a hydraulicallyoperated jack 6 operable to advance the roof support 1 toward the conveyor 5. Some roof supports, for example every fourth roof support as shown, have a second hydraulically-operated jack 7 which is operable to apply an advancing force to the conveyor 5 when its roof support is set against the roof. However, this invention is not concerned with the advance of the conveyor 5, and the operation of the jacks 7 will not be further described here. The jacks 7 may operate in the rnanner described in U.K. patent application No. 34,818/ 63. FIGURE 1 also shows a cutting machine 8 which is moving from left to right along the working face 2.

A main hydraulic pressure line 9 extends along the series of roof supports and is connected to a valve assembly 10 of each roof support by a branch line 11. A control line 12, which can be pressurised to various hydraulic pressures for purposes which will be described later, also extends along the series of roof supports, and is connected to the valve lassem-bly 10 of each roof support by a branch control line 1'3.

Each valve assembly '10' includes a secondary valve assembly #14 which is connected to the secondary valve assembly 14 of the adjacent roof support by a signal line 15. Eachsecondary valve assembly 14 includes two valves 16, 17 which can be opened by linear movement of push-rods 18, `19. The push-rods 18, 19 can be moved to open valves 16, 17 by hydraulic pressure in a charnber 21 acting on pistons 22, 23 carried by push-rods 18, 19, in which case both valves 16, 17 are opened together. The push-rods 18, 19 can also be moved by manual operation of a pivotally-:mounted lever 24, in which case the valves 16, 17 can be opened alternatively, depending upon the direction of movement of the lever 24. The pushrods 18, 19 also carry -valves 25, 26 respectively. Each signal line 15 is connected to a position between the valves 16, 25 or `17, 26 as the case may be.

When the -valve 16 is shut and valve 25 is open, as shown in FIGURE 3, the signal line 15 connected to the left hand side of the secondary valve assembly 14 is put into communication with a chamber 27 connected to a l lluid return line 3i). When valve -16 is open and valve 25 is shut, the signal line 15 connected to the left hand side of the secondary valve assembly 14 is put into communication with a chamber 28 connected to the branch supply line 11. In Ipractice, valves y16 and 25 will be so arranged that valve 25 can never be partly open when valve 16 is partly open so that chamber 28 can never be in communication with chamber 27. The signal line 15 connected to the right hand side of secondary valve assembly 14 is connected to valves 17, 26 which opeate in a similar manner to valves 16, 25 respectively.

The secondary valve assembly 14 also includes two valves 29, 31 to one of which one signal line 15 is connected and to the other of which the other signal line 15 is connected. When open, the valves 29, 31 bring the respective lines 15 into communication with a line 32 leading to the jack 6. Each valve 29, 31 carries a piston 33, 34, respectively, upon which acts a spring 35, 36 respectively, in the valve-closing sense. Each signal line 15 also includes a non-return valve 37, 38 respectively. The valve 29 is connected to its signal line 15 on the side of the non-return valve 37 remote from the secondary valve assembly 14, and the portion of the signal line y15 on the side of the nontreturn valve 37 adjacent the secondary valve assembly 14 is connected to the piston 33 so that pressure in this portion ofthe signal line 15 acts on the piston 33 in the same sense as the spring 35. The Valve 31 is similarly connected to its signal line 15.

The line 32 passes through a self-latching by-pass va'lve 39, a non-return valve 41 and a drain valve 42. The bypass valve 39 is a two position valve which opens a line 32 in one position and, in its other position, shuts off the valves 29, 31 from the non-return valve 41 and connects valves 29, 31 through line 43 and non-return valve 44 to a sequenec valve 45. The by-pass valve 39 is springbiased to the first position, shown in the drawing, and can be moved to its second position by a predetermined pressure in the branch control line 13, to which it is connected.

Line 32 is also connected through a prop re-setting valve 46 to a line 47 including a non-return valve 48 and a pressure reducing valve or restrictor 49. Line 47 is connected to the props 4 through non-return valves 51 and lines 52. Prop re-setting valve 46 can be opened by contraction of the jack 6 to almost its minimum length, or by a predetermined pressure in branch control line 13.

Lines 52 are also connected through non-return valves 53 to a line 54 leading to a prop-release valve 55 and a pressure relief valve 56. Prop-release valve 55 is operable by a pivotally-mounted lever 57, as is also a manual prop-setting valve 58, connected -to branch supply line 11 and line 47. The lever 57 is operable by a piston 59 actuated by pressure in line 32, and by a piston 61 actuated by pressure in line 47.

A line 62 connected to the portion of line 47 between va'lve 49 and non-return Valves 51 includes a non-return valve 63 and is connected to the sequence valve 45. A Llocking valve 64 connected to line 62 between sequence valve 45 and non-return valve 63 can be opened by a predetermined pressure in branch control line 13. A portion of branch control line 13 connected to chamber 21 of secondary valve assembly 14 includes the sequence va'lve 45 and a safety valve 65 which can be closed by a predetermined pressure in branch control line 13.

The drain valve 42 includes a piston valve 66 urged by a spring 67 to a position in which the portion of line 32 between the `drain valve 42 and the jack 6 is isolated from the return line 30. The piston vallve 66 contains a non-return valve 68 through which fluid can pass from the by-pass valve 39 to the jack 6. A restrictor 69 is connected to the portion of line 32 between the non-return valve 41 and the drain valve 42 and to the fluid return line 30.

The various elements in each valve assembly which are operated by predetermined pressures in the control line 12 and branch control line 13 are arranged to be operated by different predetermined pressures. In this embodiment, the pistons 22, 23 of secondary valve assembly 14 require a pressure of 400 lbs/sq. in. in chamber 21 to cause the pistons 22, 23 to shut valves 25, 26 and open valves 16, 17. The safety valve 65 shuts when the pressure reaches 800 lbs/sq. in. The prop re-setting valve 46 opens at a pressure of 1,200 lbs/sq. in., and the locking valve 64 is opened by a pressure of 2,800 lbs./ sq. in.

When the conveyor 5 has been advanced, the roof supports 1 can be caused to undergo advancing operations either automatically one after the other, or each roof support 1 can be caused to undergo an advancing operation by manual operation of the lever 24 of the secondary valve assembly 14 of the roof support 1 on either side of the roof support 1 to be advanced, as will be described later.

Firstly, the operation of the roof supports 1 advancing automatically one after the other will be described. Although the advancing sequence can be started at either end of the series, according to whether it is desired to have the advance sequence proceed from left to right or from right to left along the series, only a left to right sequence will be described. Before an advance sequence commences, each roof support 1 will be set against the roof and the various elements of its valve assembly 10 will be as shown in the drawing.

The control line 12 is rst pressurised to 400 lbs./sq. in., but this pressure does not reach chamber 21 because sequence valve 45 is closed. The signal line 15 leading to the left hand side of the secondary valve assembly 14 of the first roof support 1 is pressurised by operation of a manually-operated or remotely-controlled valve (not shown). This pressure cannot pass non-return valve 37, but opens valve 29 and pressurises line 32. The pressure passes along tline 32 lthrough the by-pass valve 39, nonreturn valve 41 and drain valve 42 to the jack 6 upon which it acts in a jack-contracting sense. At the same time, the pressure in line 32 actuates piston 59 to pivot lever 57 and open the prop release valve 55 to bring line 54 into communication with the fluid return line 30. Hence the props 4 lose their pressure and the roof support 1 is released from the roof. The jack 6 then advances the roof support 1 up to the conveyor 5.

When the jack 6 is nearly fully contracted, the jack 6 causes prop-resetting valve 46 to pressurise line 47 from line 32. Piston 61 then moves lever 57 to allow prop release valve 55 to close, and the props 4 are reset by pressurisation of line 47 from line 32. When a satisfactory setting pressure in the props 4 is achieved, this pressure which is also present in line 62 opens sequence valve 45 to cause pressurisation of chamber 21 and consequent closure of valves 25, 26 and opening of valves 16, 17. Sequence valve 45 is locked in the open position by fluid trapped in the lines between non-return valves 44, 63 and locking valve 64.

The opening of valve 16 results in closure of valve 29 due to fluid pressure from chamber 28 acting on piston 33 in the same direction as the spring 35. The opening of valve 17 pressurises the signal 'line 15 leading to the adjacent roof support 1 on the right of the roof support 1 which has just advanced, and this next roof support 1 then undergoes an advancing operation.

Both valves 29 and 31 are now held in the closed position by fluid pressure from chamber 28 assisting the springs 35, 36 respectively, and -line 32 is isolated from the signal lines 15. The pressure in the portion of line 32 between the valves 29, 31 and drain valve 62 and piston 59 drains away through 4the restrictor 69. Then the pressure in the portion of line 32 between the drain valve 42 and the jack 6, and the pressure in the portion of line 47 between the prop-resetting valve 46 and the piston 61, lifts piston valve 66 and drains to the fluid line 30.

The advance sequence could equally well proceed from right to left along the series, if the signal line 15 leading to the right hand side of the secondary valve assembly 14 of the roof support at the right hand end of the series had been pressurised.

If, during the advance, the roof support 1 met an obstruction and did not complete its advance, the jack 6 would not operate prop-setting valve 46. Hence this valve 46 would have to be opened by pressurisation of the control `line 12 to 1,200 lbs/sq. in. Safety valve 65 would close at 800 lbs./sq. in., and prevent any pressurisation of chamber 21 until the pressure in the control line 12 has been reduced back to 400 lbs/sq. in.

If any of the props 4 develop a leak, the desired setting pressure will not be achieved in the props 4 and flines 47 and 62 after the roof support 1 has advanced. Therefore, there will not be suicient pressure .in line 62 to operate the sequence valve 45. If this happens, the control line 12 is pressurised to 2,000 lbs/sq. in. to move by-pass valve 39 to its second position in Which signal line 15 and valve 29 are isolated from the jack 6 and props 4 and are brought into communication with lline 43 leading to the sequence valve 45 which is thus opened. Safety valve 65, which is shut by the 2,000 lbs./ sq. in. pressure in the control line 12, opens when the control line pressure is re* duced back to 400 lbs/sq. in. The chamber 21 is then pressurised by the pressure in the control line 12, and the pistons 22, 23 are operated by this pressure, and the signal line leading to the next roof support 1 becomes pressum'sed. By-pass valve 39 remains in its second position 'because of its sellf-latching property, fluid being trapped in line 43 and in the portion of line 32 between valves 29, 31 and by-pass valve 39, and hence isolates the leaking part of the hydraulic circuit of the roof support from the signal line 15 and valve 29, thus preventing further leakage.

When the by-pass valve 39 of a leaking roof support 1 is moved to its second position, the by-pass valves 39 of all the other roof supports 1 will be similarly moved. However, the by-pass valves 39 of the other roof supports will not self-latch, since their lines 32 Will not be pressurised.

When all the roof supports have advanced, the locking valves 64 on all the roof supports l are opened by pressurising the control line 12 to 2800 lbs/sq. in. This also causes any operated by-pass valve 39 to revert to the position shown in the drawing, since the self-latching pressure drains away through line 43 and the open locking valve 64 to the return line 30.

If it is desired to advance the roof supports 1 by manual operation of their levers 24, no pressure is put into the control line 12. On any roof support, manual operation of the lever 24 in an anti-clockwise manner to operate push-rod 18 causes a signal to be sent `along the signal line 15 leading to the adjacent left hand roof support 1, which consequently undergoes an advancing operation. Similarly, 'manual operation of the lever 24 in a clockwise manner to operate push-rod 19 results in the adjacent right hand roof support 1 undergoing an advancing operation.

The drain valve 42 also allows Huid to be expelled from the piston rod side of the jack 6 when the conveyor 5 is advanced relative to the roof support 1 with consequent extension of the jack 6. When this occurs, fluid from the jack 6 passes up line 32 to the drain valve 42 and moves the piston valve 66 against the spring 67 to open the pathway to the fluid return line 30.

In an emergency, the props 4 may -be reset by manual operation of lever 57 and setting valve 58.

We claim:

1. A roof support assembly including a series of advanceable roof supports, each roof support having at least one duid-pressure-operated prop operable to set the support aginst a roof and a uid-pressure-operated jack operable to advance the support, each roof support also having a valve assembly controlling operation of the prop and the jack, the valve assembly being operated by the receipt of a signal from the preceding roof support in the series to cause its roof support to undergo an advancing operation, and the valve assembly `being responsive to the satisfactory completion of the advancing operation of its roof support to send a signal to the next roof support in the series, the assembly also including a source of fluid pressure which, when a roof support is undergoing an advancing operation, supplies iluid under pressure through the valve assembly of the roof support to the prop and jack thereof, and isolating means operable from a position remote from the roof supports to isolate from the source of fluid pressure the prop and jack of a roof support which has received but not passed on the signal.

2. A roof support assembly according to claim 1 wherein each valve assembly includes a valve associated with a line which remains unpressurised until its roof support receives the signal from the preceding roof support, and the operation of the isolating means actuates the valve of every assembly, each valve assembly being so arranged that a valve actuated by the by-passing means isolates the associated prop and jack from the source of fluid pressure and continues such isolation after operation of the isolating means has taken place if the line associated with the valve is pressurised.

3. A roof support assembly according to claim 2 wherein the signal is a fluid-pressure-signal which supplies the fluid pressure for the line.

4. A roof support assembly according to claim 3 wherein the huid-pressure signal originates from the source of fluid pressure and passes through the valve assembly to the prop and jack, and the isolating means functions by isolating the signal from the prop and the jack.

5. A roof support assembly including a series of advanceable roof supports, each roof support having at least one lluid-pressure-operated prop operable to set the support against a roof and a fluid-pressure operated jack operable to advance the support, each roof support also having a valve assembly controlling operation of the prop and the jack, the valve assembly being operated by the receipt of a signal from the preceding roof support in the series to cause its roof support to undergo an advancing operation, and valve assembly being responsive to a satisfactory completion of an advancing operation of its roof support to send a signal to the next roof support in the series, the valve assembly including a line whose pressurisation causes release of the prop from a roof-supporting condition and actuation of the jack in a supportadvancing manner, and the valve assembly operating to release pressure from said line when the signal is sent to the next roof support.

6. A roof support assembly according to claim 5 wherein the signal is a uid pressure signal which supplies the fluid pressure for the line.

No references cited.

EDGAR W. GEOGHEGAN, Primary Examiner. 

1. A ROOF SUPPORT ASSEMBLY INCLUDING A SERIES OF ADVANCEABLE ROOF SUPPORTS, EACH ROOF SUPPORT HAVING AT LEAST ONE FLUID-PRESSURE-OPERATED PROP OPERABLE TO SET THE SUPPORT AGAINST A ROOF AND A FLUID-PRESSURE-OPERATED JACK OPERABLE TO ADVANCE THE SUPPORT, EACH ROOF SUPPORT ALSO HAVING A VALVE ASSEMBLY CONTROLLING OPERATION OF THE PROP AND THE JACK, THE VALVE ASSEMBLY BEING OPERATED BY THE RECEIPT OF A SIGNAL FROM THE PRECEDING ROOF SUPPORT IN THE SERIES TO CAUSE ITS ROOF SUPPORT TO UNDERGO AN ADVANCING OPERATION, AND THE VALVE ASSEMBLY BEING RESPONSIVE TO THE SATISFACTORY COMPLETION OF THE ADVANCING OPERATION OF ITS ROOF SUPPORT TO SEND A SIGNAL TO THE NEXT 